(1) Field of the Invention
This invention relates to a gearing transmission equipped with planetary transmission apparatuses. More particularly, it relates to such gearing transmission in a work vehicle equipped with a dozer and/or a bucket, namely the work vehicle requiring the function of change-speed in quite many steps.
(2) Description of the Prior Art
As the change-speed apparatus in a work vehicle equipped with a dozer and/or a bucket, it is now preferred or normally prevailing to use an oilhydraulic type drive-power transmission apparatus. It is noted, however, that such type of the apparatus is rather poor in the power transmission efficiency, and it is thus the trend to reconsider use of the transmission of gearing engagement type.
Particularly preferable in such trend of the use for the said type of work vehicle are the planetary transmission apparatuses, since they can provide the speed reduction in quite a wide range.
Thus, the problems herein encountered so far are the ways how to construct the planetary transmission apparatuses and how to dispose or incorporate them in the entire gearing transmission system, in order to realize the desired multiple-stage speed-changing function in simple and inexpensive overall structure. For instance, it is a problem, in the case of using two sets of the planetary transmission apparatuses, how to interconnect them in order to provide the entire structure as is most efficient and reasonable.
Such problem can not be solved simply by fractional or local design modification of the conventionally prevailing gearing transmission system, but rather requires entirely new construction of the whole system as must be built up from nothing at all thus on the ground or principle of quite innovated technical ideas.